aneurysm
Pronunciation: AN-yur-izm
Abnormal focal dilatation of an artery wall that exceeds 150% of the normal vessel diameter.
Full Definition
An aneurysm is a localized, abnormal dilatation of an arterial wall that represents a structural weakness in the vessel. True aneurysms involve all three layers of the arterial wall (intima, media, and adventitia), while pseudoaneurysms result from contained rupture with hematoma formation. Aneurysms are classified by location (cerebral, aortic, peripheral), morphology (fusiform or saccular), and size. The risk of rupture generally increases with aneurysm size and growth rate. Imaging plays a crucial role in aneurysm detection, characterization, surveillance, and treatment planning, with different modalities offering complementary information about aneurysm anatomy and hemodynamics.
Usage
Usage note: Specify type (true vs. pseudo) and morphology (saccular vs. fusiform) when relevant.
In Context
- "The abdominal aortic aneurysm measured 5.2 cm in maximum diameter." — CT scan report
- "A small saccular aneurysm was identified at the anterior communicating artery." — Cerebral angiography report